Stepwise evolution from a focal pure pulmonary ground-glass opacity nodule into an invasive lung adenocarcinoma: An observation for more than 10 years

The natural chronologic evolution of a lung cancer manifesting as a pure ground-glass opacity (GGO) nodule on CT scans still remains to be elucidated. Therefore, it is sometimes difficult to determine proper follow-up examinations, particularly in case of GGO nodule growing slowly on serial CT scans. In the current case, we demonstrate serial morphologic (CT) and metabolic (¹⁸F-FDG PET) imaging findings in a case of adenocarcinoma, where stepwise progression from a focal pure GGO nodule (presumed atypical adenomatous hyperplasia [AAH] or bronchioloalveolar carcinoma [BAC]) eventually to an invasive adenocarcinoma was clearly depicted for more than 10-year follow-up period. This case seems to be useful for the prediction of tumor growth pattern and aggressiveness of malignant pure GGO nodules. In addition, the evolving process of this case may suggest a guideline for planning an appropriate follow-up examination and management in such cases.